science does not always = the truth as you put it....
science = the search for truth.
the example you give of the holocaust deniers was not a scientific experiment because they obviously lied about the sites they tested. you don't lie in a true cientific experiment. the reason i say science is the search for truth is because it is always changing. science never comes up with an answer that is concrete. instead science invites others to try to prove it wrong, in this way there is a constant forward motion of discover which will eventually lead to the truth. i will give an example: people used to think that the earth was the center of the universe. eventually with the help of the mathematical theorems (which you call abstractions) it was proven that the earth is far from the center and that it is the one that is spinning around the sun and not the other way around. later with the same "abstract" math, we built ships that could take us into space so we could see for our selves. in this case real science which evolved over many years lead us to the truth.
if your interested, there is a book called "zero" by charles seife that will show you how real and applicable math is.
\"One murder makes a villain...millions a hero. Numbers sanctify, my friend.\" -Charlie Chaplin